Function DrawDash

xgeneral.cpp:603–776

// is a specified a skip factor, which allows drawing dashed lines.

void DrawDash(int x1, int y1, int x2, int y2, int skip)
{
  int x, y, i, dx, dy, xInc, yInc, xInc2, yInc2, d, dInc, z, zMax;

  if (skip < 0)
    skip = 0;
  else if (skip > 0 && gs.fThick)
    skip++;
#ifdef ISG
  if (!gi.fFile) {
    if (!skip) {
#ifdef X11
      // For non-dashed X window lines, have the Xlib do it.

      XDrawLine(gi.disp, gi.pmap, gi.gc, x1, y1, x2, y2);
      // Some XDrawLine implementations don't draw the last pixel.
      XDrawPoint(gi.disp, gi.pmap, gi.gc, x2, y2);
      if (gs.fThick) {
        // Make the line thicker by drawing it four times.
        XDrawLine(gi.disp, gi.pmap, gi.gc, x1+1, y1, x2+1, y2);
        XDrawLine(gi.disp, gi.pmap, gi.gc, x1, y1+1, x2, y2+1);
        XDrawLine(gi.disp, gi.pmap, gi.gc, x1+1, y1+1, x2+1, y2+1);
        XDrawPoint(gi.disp, gi.pmap, gi.gc, x2+1, y2);
        XDrawPoint(gi.disp, gi.pmap, gi.gc, x2, y2+1);
        XDrawPoint(gi.disp, gi.pmap, gi.gc, x2+1, y2+1);
      }
#endif
#ifdef WINANY
      if (x1 == x2 && y1 == y2) {
        DrawPoint(x1, y1);
        return;
      }
      MoveTo(wi.hdc, x1, y1);
      LineTo(wi.hdc, x2, y2);
      if (wi.nScaleWin > 1)
        return;
      if (!gs.fThick) {
        // For Windows lines, have to manually draw the last pixel.
        SetPixel(wi.hdc, x2, y2, (COLORREF)gi.kvCur);
      } else {
        // Make the line thicker by drawing it four times.
        i = gi.nScaleT;
        LineTo(wi.hdc, x2+i, y2);
        LineTo(wi.hdc, x1+i, y1);
        LineTo(wi.hdc, x1,   y1+i);
        LineTo(wi.hdc, x2,   y2+i);
        LineTo(wi.hdc, x2+i, y2+i);
        LineTo(wi.hdc, x1+i, y1+i);
        LineTo(wi.hdc, x1,   y1);
      }
#endif
      return;
    }
#ifdef WIN
    if (skip && wi.nScaleWin > 1)
      skip = (skip + 2)*wi.nScaleWin + gs.nThickAdjust - 1;
#endif
  }